The date on some of those posts in interesting. 2009 is quite a while ago now, and I'd suggest that columnar datastores haven't exactly taken over. Some implementations have made some progress (eg Cassandra), but OTOH many non-traditional datastores have added traditional-database like features (eg, Facebook's SQL front end on their NoSQL system), and traditional databases have added NoSQL features too.
Stonebraker is a very smart person but he's also not shy about promoting his own companies/research. You generally get a well-informed but very opinionated take on things from him.
VoltDB, for example, is good for certain complex workloads over large but not-too-large data sets. For a lot of situations it isn't really an alternative to memcache+MySQL or a NoSQL solution.
In particular, his criticism of traditional databases seems based more on philosophy rather than evidence.
I'd advise reading both sides of the story:
http://lemire.me/blog/archives/2009/09/16/relational-databas...
http://lemire.me/blog/archives/2009/07/03/column-stores-and-...
http://architects.dzone.com/articles/stonebraker-talk-trigge...
http://gigaom.com/2011/07/11/amazons-werner-vogels-on-the-st...
http://dom.as/2011/07/08/stonebraker-trapped/
The date on some of those posts in interesting. 2009 is quite a while ago now, and I'd suggest that columnar datastores haven't exactly taken over. Some implementations have made some progress (eg Cassandra), but OTOH many non-traditional datastores have added traditional-database like features (eg, Facebook's SQL front end on their NoSQL system), and traditional databases have added NoSQL features too.